{"id":63725,"date":"2022-03-30T14:22:00","date_gmt":"2022-03-30T18:22:00","guid":{"rendered":"https:\/\/www.shortform.com\/blog\/?p=63725"},"modified":"2022-04-06T14:42:48","modified_gmt":"2022-04-06T18:42:48","slug":"left-brain-interpreter","status":"publish","type":"post","link":"https:\/\/www.shortform.com\/blog\/left-brain-interpreter\/","title":{"rendered":"The Left Brain Interpreter and Sense-Making"},"content":{"rendered":"\n

What is the “left brain interpreter”? How does the brain assimilate new information? <\/p>\n\n\n\n

The left brain interpreter is a neurophysiological concept that refers to the brain’s process of making sense of new information by relating it to existing knowledge. Although the concept was based on the studies of split-brain patients\u2014patients who had their corpus callosum severed\u2014it applies to neurotypical populations at large. <\/p>\n\n\n\n

Keep reading to learn about the left brain interpreter and its role in sense-making.<\/p>\n\n\n\n\n\n\n\n

The Interpreter Within<\/h2>\n\n\n\n

Humans have a strong need for a sense of coherence and continuity, and the left-brain interpreter can be seen as the glue that holds the pieces of a narrative together. Research with split-brain patients may offer some clues about how it works.<\/p>\n\n\n\n

Split-brain patients are people who have had their corpus callosum\u2014the tract of nerve fibers that connects the left and right hemispheres\u2014severed to treat severe epilepsy. In someone with an intact corpus callosum, the right and left hemispheres can communicate directly. This means that the left hemisphere is aware of the perceptions and actions of the right hemisphere (such as moving the left side of the body and seeing things in the left visual field) and vice versa. But in a split-brain patient the two hemispheres are cut off from one another.<\/p>\n\n\n\n

Michael Gazzaniga and colleagues investigated what happens when there\u2019s different input to the two hemispheres of split-brain patients<\/a>. In most people, language is a left-hemisphere function. The team found that when they presented stimuli to the left hemisphere (for example flashing an image in the right visual field), the patient could easily name and describe the image. If a picture of an object was presented to the right hemisphere, patients verbally denied seeing anything, but could select that picture from an array of different pictures using their left hand. <\/p>\n\n\n\n

When different images were flashed simultaneously to the two hemispheres, split-brain patients could only report verbally on the right-hand one. For example, one patient\u2019s right hemisphere was shown a picture of a chicken\u2019s foot and his left hemisphere a picture of a snowy landscape. Afterward, he pointed immediately to a picture of a whole chicken and a picture of the shovel. When asked why he\u2019d chosen the shovel (information that the verbal left hemisphere had no access to), he said easily, \u201cYou need the shovel to clean out the chicken shed.\u201d<\/p>\n\n\n\n

The Problem With Rationalizing<\/h3>\n\n\n\n

There are two problems with rationalizing:<\/p>\n\n\n\n

Problem #1:<\/strong> Rationalizing leads to inaccurate explanations of our decisions.<\/strong><\/p>\n\n\n\n

Gladwell discusses the Problem of the Two Ropes to demonstrate how far our rational explanations can veer from the truth. In a 1931 study, psychologist Norman Maier hung two ropes from the ceiling<\/a> in a room that also contained various items of furniture and other tools. The ropes were far enough apart that if you held one rope in your hand, you couldn\u2019t reach the other. He asked volunteers to come up with as many ways to tie the two ropes together as they could. There were three obvious solutions using the furniture and tools provided, which most people figured out fairly easily. There was also a fourth, non-obvious solution: set one of the ropes swinging, go stand next to the other, and grab the swinging rope before tying them together.<\/p>\n\n\n\n

If a volunteer was having trouble producing this fourth solution, the psychologist walked across the room and casually bumped into one of the ropes, causing it to swing. The move was so subtle that volunteers\u2019 unconscious minds picked up on the suggestion while their conscious minds didn\u2019t.<\/strong> After that, most people came up with the fourth solution.<\/p>\n\n\n\n